In-plane sensor, out-of-plane sensor, and method for making same

Abstract

According to the present invention, an in-plane sensor comprises a structure unit which includes: a fixed structure including a fixed finger and a fixed column connected to each other, the fixed finger having a supported end supported by the fixed column and a suspended end; and a movable structure including at least one proof mass which surrounds the fixed finger in a horizontal plane.

1. An in-plane sensor, comprising:
 a fixed structure including a fixed finger and a fixed column connected to each other, the fixed finger having a supported end supported by the fixed column and a suspended end; 
 a movable structure including at least one proof mass which surrounds the fixed finger in a horizontal plane; 
 an anchor; and 
 a spring connecting an outer side of the proof mass to the anchor, 
 wherein by surrounding the fixed finger the proof mass forms an opening, and in additional to the opening surrounding the fixed finger, the proof mass has at least another opening or semi-opening for reducing a continuous length of the proof mass to reduce bending, wherein the at least another opening does not surround the fixed finger, any other fixed finger, the spring, and any other spring. 
 
     
     
       2. The in-plane sensor of  claim 1 , comprising two or more movable structures separated from one another and connected together by one or more connecting parts. 
     
     
       3. The in-plane sensor of  claim 2 , wherein the two or more movable structures have substantially the same size and layout from top view. 
     
     
       4. The in-plane sensor of  claim 2 , wherein each of the movable structures has the same layout as compared with another movable structure, but is 0° , 90° , 180° , or 270° rotated. 
     
     
       5. The in-plane sensor of  claim 2 , wherein each of the connecting parts is not a side of any opening surrounding the fixed finger or any other fixed finger. 
     
     
       6. The in-plane sensor of  claim 1 , wherein the proof mass has a plurality of openings which do not surround the fixed finger and any other fixed finger, and these openings are distributed uniformly in the proof mass. 
     
     
       7. The in-plane sensor of  claim 1 , wherein the horizontal plane has an x dimension and a y dimension perpendicular to each other, and wherein the continuous length of the proof mass is limited under 100 μm in at least one direction along the x or y dimension. 
     
     
       8. The in-plane sensor of  claim 1 , wherein the proof mass has at least one semi-opening at a periphery side of the proof mass to reduce a continuous length of the periphery side of the proof mass. 
     
     
       9. An out-of-plane sensor, comprising:
 a fixed structure including at least one fixed part; and 
 a plurality of movable structures each including a movable part above or below the fixed part, the movable structures being separated from one another and connected together by one or more connecting parts, wherein each of the connecting part is not a side of any opening surrounding a part of the fixed structure, 
 wherein at least one of the fixed part or at least one of the movable parts includes a plurality of uniformly distributed openings for reducing a continuous length of the fixed part or the movable part to reduce bending, and 
 wherein each of the movable structures is movable vertically to vary a distance between the movable structure and the fixed structure. 
 
     
     
       10. The out-of-plane sensor of  claim 9 , wherein the fixed structure includes an upper fixed part and a lower fixed part, and wherein the movable parts of the plurality of movable structures are located between the upper and lower fixed parts. 
     
     
       11. The out-of-plane sensor of  claim 9 , further comprising a spring and an anchor, and wherein the movable parts are connected to the anchor by the spring. 
     
     
       12. The out-of-plane sensor of  claim 11 , wherein the fixed structure and the plurality of movable structures form one capacitive unit, and the out-of-plane sensor comprises four springs and four anchors located at four sides of the movable structures. 
     
     
       13. The out-of-plane sensor of  claim 9 , wherein the fixed part and each movable part have a horizontal plane having an x dimension and a y dimension perpendicular to each other, and wherein the continuous length of at least one of the fixed part or at least one of the movable parts is limited under 100 μm in at least one direction along the x or y dimension. 
     
     
       14. The out-of-plane sensor of  claim 9 , wherein the plurality of movable structures have substantially the same layout from top view. 
     
     
       15. The out-of-plane sensor of  claim 14 , wherein each of the movable structures has the same layout as compared with another movable structure, but is 0°, 90°, 180°, or 270° rotated. 
     
     
       16. The in-plane sensor of  claim 9 , wherein the at least one fixed part or the at least one movable part which includes the plurality of uniformly distributed openings further includes at least one semi-opening at a periphery side of the at least one fixed part or the at least one movable part to reduce a continuous length of the periphery side of the at least one fixed part or the at least one movable part.